Power drive for windshield cleaners



July 13, 1954 M. BITZER POWER DRIVE FOR WINDSHIELD CLEANERS 4 Sheets-Sheet 1 Filed Dec. 8, 1950 INVENTOR. Mart/n fi/zfzer M. BITZER POWER DRIVE FOR WINDSHIELD CLEANERS July 13, 1954 4 Sheets-Sheet 2 Filed Dec. 8, 1950 INVENTOR. Mart/'12 5/622/ July 13, 1954 M. BITZER 2,683,275

' POWER DRIVE FOR WINDSHIELD CLEANERS 4 Sheets-Sheet 5 Filed Dec. 8, 1950 I09 /06 lg 75 Z M 125 22 w /z7 i 2 //z w INVENTOR. Mari/'17 Eliza-x" July l3, 1954 M. BITZER POWER DRIVE FOR WINDSHIELD CLEANERS 4 Sheets-Sheet 4 Filed Dec. 8, 1950 INVENTOR. Nam/72 5/52 Patented July 13, 1954 UNITED STAT FATENT OFFICE POWER DRIVE FOR WINDSHIELD CLEANERS Martin Bit-zer, Kenmore, N. Y., assignor to Trico Products Corporation, Bulfalo, N. Y.

Application December 8, 1950, Serial No. 199,811

Claims.

across a windshield surface whereby to cleanse predetermined areas thereof.

It is an object of this invention to provide a windshield cleaner wherein the driving means are both quiet and positive in operation.

Another object of this invention is to provide a windshield cleaner which is powerful, by reason of its having dual driving motors, and at the same time is compact, so as to occupy a minimum amount of space.

A further object of this invention is to provide a windshield cleaner having simplified automatic control means serving to impart an oscillatory motion to the wiper blades.

In addition, it is an object of this invention to provide a windshield cleaner incorporating means permitting the wiper blades to traverse a predetermined fixed path of movement without contacting the edge portions of the windshield and causing the wiping blades to assume a parked position adjacent the bottom edge ofthe windshield.

With the foregoing and. other objects in view,

this invention comprises certain novel features and combinations of parts to be fully disclosed in the ensuing detailed description.

For a better understanding of the present invention, reference is hereby made to the accompanying drawings in which like reference numerals are used to denote like parts throughout the various views and in which:

Fig. 1 shows the entire windshield cleaner assembly installed in place on the front portion of a vehicle;

Fig. 2 is a side view looking to the. right in Fig. 1 showing the dual suction motors used to drive the windshield cleaner together with the donkey engine control means therefor;

Fig. 3 is a fragmentary side view similar to.

Fig. 2 but looking to the left in Fig. 1;

Fig. 4 is a sectional view of one of the suction motors taken along the line IV-IV of Fig. 2;

Fig. 5 is a view of the donkey engine, partly in section, taken along the line V--V of Fig. 3;

Fig. 6 is a side view, partly in section, of the donkey engine;

Fig. '7 is a sectional view of the donkey engine taken along the line VIIVII of Fig. 6;

Fig. 8 is a fragmentary view taken along the line VIIIVIII of Fig. 6 and showing the donkey engine controller in running position;

Fig. 9 is a fragmentary plan view similar to: Fig. 8 but showing the donkey engine controller in park position;

Fig. 10 is a plan View, partly in section, of a modified form of donkey engine;

Fig. 11 is a sectional view taken along the line XI-XI of Fig. 10;

Fig. 12 is a sectional view taken along the line XIl -XII of Fig. 10; and

Fig. 13 is a fragmentary plan view of the controller for the modified donkey engine.

Despite the many technical advances which have been made in the windshield cleansing art, numerous problems have remained unsolved.

For example, one of these problems is the com-' monly experienced slapping of the wiper blades against the windshield molding. The noise thus produced is a source of constant irritation to the operator of a vehicle, and is a potential source of danger in that it tends to detract from the Operators concentration on his driving. Previous attempts to solve this problem have for the most part proved unsatisfactory, since they frequently require a reduced sweep of the wiper blade, or;

must be produced if the windshield cleaner is to.

operate satisfactorily.

The present invention solves these and other existing problems, in accordance with the aforesaid objects, as will become apparent from the following description.

Basically, the present invention comprises a windshield cleaner having dual suction motors connected to the wiperblades by an endless drive.

arrangement and with a single donkey engine control means for both said motors.

The dual suction motors are mounted in single unitary casing I having end plates 2 and 3 secured thereto by means of a plurality of bolts 4 and 5. Motor casing I is secured at one side to a bracket 5 by means of bolt 1, bracket 6 being adapted for attachment to some part of the vehicle such as the firewall thereof, not illus; trated, by any conventional means.

Mounted on the other side of motor casing I is a donkey engine 8 having ears Q and Ill which are secured to said casing by means of bolts ll and it. A vacuum line i3 extends from donkey engine ii and is secured to a coupling l4 in the air intake iii of carburator iii. A connection H extends between carburetor l5 and intake manifold it, which latter is in turn connected to engine block it. A Bcwden wire 29 extends from the donkey engine 3 to the drivers compartment of the vehicle, as shown.

Motor casing has two cylindrical bores 21 and '22 therein. Each of cylindrical bores 2i and 22 has a piston rod 23 and 24, respectively, journaled for reciprocating movement therein. Piston elements 25 and 26 are mounted on piston rods 23 and as, respectively, to impart a back and forth or reciprocatory movement thereto. Attaching caps 21' and 28 are threadedly mounted on each end of piston rod 23, and attaching caps '29 and as are threadedly mounted on each end of piston rod 24. A flexible cable 3! is attached at one end to attaching cap 2? and at its other end to attaching cap 29. Cable 3| extends around pulleys 32 and 33 which are attached to the vehi cle, and around a rockshaft 34 in driving engagement therewith. A flexible cable 35 is attached at one end to attaching cap 28 and at its other end to attaching cap 39. Cable 35 extends around pulleys 35 and 3i, which are attached to the vehicle, and around a rockshaft 33 in driving engagement therewith. In this manner, cables 3! and 35 and piston rods 2? and 24 combine to form in effect an endless drive. An actuating arm 39 carrying a wiper blade .5) at its outer end is mounted at its inner end on roclrshaft 34, and an actuating arm 4i carrying a wiper blade 42 on its outer end is mounted upon rockshaft 38. Therefore a back and forth movement of piston rods 23 and 24 will impart an oscillatory motion to wiper blades 49 and 42, causing them to cleanse predetermined areas of the windshield.

Referring more in detail to the suction motor, particularly as shown in Fig. 4 oi the drawings, it is seen that piston rod 23 is composed of two members 53 and 44. Member 43 is journaled in bearing 45 on end wall 2 and is held in sealed relation therewith by means of packing gland 46 which is secured to bearing 45 by means of a cover plate 41. Similarly, member 44 is journaled in bearing 48 on end wall 3 and maintained in sealed relation therewith by means of packing gland 49 and secured to bearing 48 by means of a cover plate 56. Member 44 has an inner end portion of reduced diameter which. fits within a threaded opening 52 on the inner end of a member d3. Said portion 5! provides a shoulder 53 on member M. Piston element 25 is mounted on reduced portion 5! with. one side bearing against shoulder 53 and its other side bearing against a nut 54 held in place on reduced portion 5| by the inner end of member 43. Piston rod 24 is formed in a manner identical with piston rod 23.

Piston element 25 comprises a center plate 55 of less diameter than bore 2! and a ring 56 of the same thickness as plate 55 mounted therearound and abutting against the wall of bore 2 I. Plates 5'! and 58 are pressed against each side of plate Stand ring 55. Flexible washers 59 and 60, of a diameter larger than bore 2!, lie against plates 5! and 58 respectively, and have metallic washer elements 6! and 62 at the respective centers thereof. Plates 53 and 64 bear against washers 59 and 6!, and it and 62, respectively, and are held in place thereagainst by means of nut 54 and shoulder 53. Piston element 26 is formed in a manner identical with piston element 2 5.

Within motor casing I, and extending longitransverse ports 84 and 35.

tudinally thereof, are two passageways 65 and 66. At its left hand end, as viewed in Fig. 5, passageway 65 communicates with bore 22 through port 61, and at its right hand end passageway (i5 communicates with bore 2| through a port 63. Passageway 66 communicates at its left hand end with bore 2| through a port 69, and communicates at its right hand end with bore 22 by means of a port it. It is noted at this time that the right hand end of Fig. 4 corresponds to the left hand end of Figs. 1 and 5.

Passageways 65 and 55 are alternately and reversibly connected, in a manner to be described, to the atmosphere and to a vacuum creating means, whereby to create a reversible pressure differential acting against piston elements 25 and 25. In this manner, piston elements 25 and 2B are driven back and forth in opposite directions causing the endless cable to oscillate wiper blades 423 and 42 back and forth across the windshield in a fixed path of movement.

The donkey engine 8, shown in detail in Figs. 5, 6 and 7, comprises a cast body portion 'H having end mounting rings 12 and I3 formed integral therewith. Attaching ears 3 and Hi, previously referred to, are formed integral with body portion 1!, and threaded bolts H and i2 extend through ears 9 and It and serve to attach donkey engine 8 to motor casing l. Flexible diaphragms M and T5 are mounted in place with mounting rings 12 and I3, and end caps 16 and T! are mounted in place on the outer side of mounting rings '32 and I3, serving to lock flexible diaphragms I4 and 75 in place therein.

Vacuum line It is connected to a longitudinal exhaust passageway '58 within body portion 7!, which passageway communicates with .the exterior of body portion ii through vertical ports [9 and 80. Body portion H also has vertical passageways 8|, 82 and 83 extending from the top portion thereof to a point near the bottom thereof. Passageways 8i and 82 are placed in communication with the exterior of body portion ll at their lower ends by means of horizontal Body portion ll also has a horizontal transverse passageway 36 which communicates with passageway 83 at its forward end. and extends to the rear side of body portion H. Another transverse horizontal passageway 8! extends completely through body portion H. Passageway B5 is in communication with a port 88 in motor casing l, and passageway 87 is in communication with a second port 89 in motor casing i Ports 8B and $9 communicate with longitudinal passageways and 65, respectively.

Body portion 1! has a recess 9!! on its underside, and a longitudinal opening 8! in the front wall of said recess. A filter packing 92 is placed within said recess 90, and is held therein by means of a cover plate 93. Cover plate 93 is apertured, as at 9'4 and it attached to the underside of body portion H by means of a threaded bolt 95. Cover plate 93 extends around the inner side of mounting rings 12 and i3 and into engagement with the top of body portion H. Thus, through the use of control means presently to be described, passageways 65 and 66 can reversibly and alternately be placed in communication with the atmosphere and with vacuum line i 3, whereby to create a reversible pressure differential acting against piston elements 25 and 26.

Plates 96 and 9'! are mounted on each side of the central portion of flexible diaphragm i5, and corresponding plates 98 and. 99 are mounted on each side of the central portion of flexible diaphragm I4. Plate 91 is adapted to abut against raised cylindrical portion I on end cap 11, and plate 98 is adapted to abut against raised cylindrical portion IOI on end cap I6. A U-shaped guide member I02 extends between flexible diaphragms T4 and I5. Guide member I02 is connected at one end I03 to plates 98 and 99 and flexible daphragm I4 by means of a rivet I04, and at its other end I to plates 96 and 91 and flexible diaphragm 75 by means of a rivet I06, the arrangement being such that diaphragms I4 and I5 and guide member I02 move together in the same direction.

Guide member I02 has a cut-out portion I01- therein with a flange I08 extending outwardly therefrom in the form of an L. A valve element I09 having a recess I I0 is securely mounted within guide member I02, and bears against body portion II. Valve element I09 is spring biased against body portion II by means of a spring II I extending between flange I08 and a boss I I2 on valve element I09. Valve-element I09 is so mounted on guide member I02, and recess H0 is-of such size, as to place port 84 in communication with either port 65 or passageway 81, depending upon the position of diaphragms l4 and I5, the other of port 85 or passageway 3'I being in communication with the atmosphere. The complete operation of valve element I99 will be explained in detail subsequently, and as will more fully appear hereinafter valve element I09 comprises a power valve for reversing the pressure diiierential in the motors.

Mounted for movement across the top of body portion II is a plate II3 having openings H4 and H5 therein. Opening H4 is of a shape to place passageway 0| in communication with port I9, and opening H5 is of a shape to place passageway 03 in communication with either passageway 82 or port 80, depending upon the position of plate I I3. A cover plate I I6 is placed on top of plate H3, and a plate III having depending side walls fits over cover plate H6 and around plate Body portion II has a raised boss I I8 at one end of the top thereof, which boss has a groove therein. A correspondingly grooved cover plate H9 is mounted thereon by means of bolt I20. Bowden wire 20 is received within said grooves and extends longitudinally therethrough. Plate I I! has two spaced raised portions I2I and I22 thereon. Bowden wire 20 extends through raised portion I2I and is attached to a wedge I23 which fits between raised portions I2I and I22. In this manner actuation of Bowden wire 20 causes plate I I3 to change position on the top of body portion II. A projection I24 on plate II! is adapted to abut boss H8 and forms a stop member. Plates I I3, H6 and I I! are held against the top of body portion II by means of a cover member I25 which extends over plate III and is secured to a projection I26 on body portion II by means of bolt I2I. Cover member I25 is cut away so as to longitudinally receive raised portions I2I and I22.

The flexible diaphragms I4 and I5 are actuated by a reversible pressure diflerential, in the following manner.

Horizontal transverse passageways I28 and'I23' extend from the space between flexible diaphragm I4 and end cap I6. and flexible diaphragm I5 and end cap 11, respectively, to the rear of body portion II. There they communicate with ports I30 and I3! which form one end of longitudinal passageways I32 and I33 in motor casing I. At their other end, passageways I32 and I33 communicate with passageways I34 and I35 in end caps 2 and 3, respectively. Passageways I34 and I35 extend to recesses I36 and I3! in said respec tive end caps.

A valve element I38 is mounted for longitudinal movement within recess ISI, and has an end I39 of the diameter of the recess, a member 140 of the diameter of the recess but having grooves therein, and a boss [M on the other end thereof. An apertured plate I42 covers one end of recess I37, and a spring I43, extending between plate I42 and end I39 of valve element I33 biases the latter to its innermost position. The other end of recess I3I has an opening I44 of reduced diameter which will receive boss I4! but not member I40.

A parking valve element I45 is journaled in the inner wall of recess I36, which wall has an opening I46 therein. A boss I41 of reduced diameter extends from parking valve I45 and has an en larged portion I45 thereon. A helical spring I49 is secured to boss I41 and raised portion hi8, and extends into abutting engagement with piston element 25.

against the inner end of recess I30. Recess I36 is enlarged throughout a portion of its length, and a recessed member I52 is mounted for sliding movement within said enlarged portion. A correspondingly recessed member I53 is threadedly mounted in the outer end of recess I36, the recesses or members I52 and I53 cooperating to hold the opposite ends of a compression spring I54. Members I52 and I53 are apertured with th conical tip I5I of end portion I50 adapted to seal the aperture in member I52. A spring I55 is interposed between end portion 555 and member I52. In addition, stop members I55 and I5I are provided on the inner side of end walls 2 and 3 respectively, so as to provide positive stop means for piston element 25.

. It is noted that valve elements I35 and I05 are provided only in conjunction with bore 2!, but serve to control both motors and in effect comprise pilot valve means controlling the donkey engine power valve means.

The operation of this invention is as follows:

As illustrated, the windshield cleaner has been stopped with wiper blades and 42 assuming a parked position along the bottom edge of the windshield. However, Bowden wire 20 has just been actuated to move cover plate I I3 to its running position as shown in Fig. 8, whereby to initiate a windshield cleansing operation. In this position a cover plate II3, the left hand side of piston 25 and the right hand side of piston 20, as viewed in Figs. 1 and 5, are subject to exhaust through ports 69 and I0, passageway 66, port 85, and passageways B6 and 53, the opening H5 in cover plate II3, passageway 82, port 85, recess H0 in valve member I09, port 84, passageway 8i, opening H4 in cover plate II3, port I9, passage- Way I8 and vacuum line I3. The right hand end of piston 25, and the left hand end of piston 25, as viewed in Figs. 1 and 5, are subject to atmospheric pressure through ports 68 and BI, passageways 65, port 09, passageway 6?, the interior of cover plate 93, opening 9I, filter packing 92, and opening 94. Since the piston elements are already at the positions to which the pressure differential thus created tends to move them, they will not move.

However, during the previous parking move ment of piston element 25, flexible diaphragms I4 and I5 will have flipped over to the left as At its other end, valve I has an enlarged end portion I with a conical tip I5I thereon. End portion I50 is adapted to abutviewed in Figs. and 6, carrying valve member I09 with them. This occurs because valve element I38, being biased to its innermost position, places the area between flexible diaphragm I5 and. cap ll in communication with the atmosphere through passageway IZQ, port I3I, passageways I33 and I35, recess I37, and the aperture in plate I52. At the same time, the area between flexible diaphragm It and end cap it is subjected to a partial vacuum through passageway E28, port 139, passageways 132 and I34, recess I35, opening H1 6, and the area between piston element 25 and end wall 3;, which area is subjected to a partial vacuum as previously explained.

Therefore the flexible diaphragms l4 and will have flipped over with valve member H19 placing port es in communication with passageway 8'5, and leaving port 85 open to the atmosphere.

In this position of valve member $99, with cover plate I i3 still in running position, the right hand side of piston element 25, and the left hand side of piston element as viewed in Fig. 1, will be subject to an exhaust action through ports 68 and 6?, passageway t5, port passageway 81, recess 5 it, port B l, passageway s I, opening I I4 in cover plate 5 l3, port it, passageway '58, and vacuum line I3. At the same time, the left side of piston element 25, and the right hand side of piston element 26, as viewed in Fig. are subjected to atmospheric. pressure through ports $5 and it, passageway 56, port 88, passageways 86 and 33, opening H5, passageway e2, port 85, the interior of cover es, opening 9i, filter packing Q2, and opening es. The pressure differential thus created will drive piston elements and 26 to the right and left respectively, as viewed in Fig. l, causing wiper blades All and 2 to move to their outermost position on the windshield.

As soon as piston element 25 moves to the right, as viewed in Fig. l, the left as viewed in Fig. 4, spring let will move member 552 against the inner end of the enlarged portion of recess I36, and spring r55 will force end portion I56 of valve Hi5 against the inner wall of recess I36. This places the area between flexible diaphragm "M and end cap it in communication with the atmosphere through the apertures in members I52 and recess passageways I34 and I32, port ifill, and passageway I28. As soon as. piston member 25 reaches its dotted line position as shown in Fig. 4, it will abut boss I4! to force valve element I38 inwardly against the action of spring This will place the area between flexible diaphragm "i5 and end cap a? in communication with vacuum line l3 through opening I44, the grooves in member 143, recess I32, passageways I and I33, port HI and passageway I29. In this manner the pressure differential on diaphragm members 74 and I5 is reversed, causing them to ilip back to t e position shown in Figs. 5 and 6. When this occurs, the pressure differential acting against piston elements 25 and 26 is reversed, placing the left hand side of piston element 25, and the right hand side of piston element 26, as viewed in Fig. l, in communication with vacuum. line it, and the right hand side of piston element 2'5 and the left hand side of piston element 26 in communication with the atmosphere, as previously explained. Piston elements 25 and 26 will then move to the left and to the right respectively, as viewed in Fig. 1, causing wiper blades as and H to return to their inner position which will be slightlyaway from the bottom edge of the windshield.

As soon as piston element 25 moves to the left as viewed in Fig. 1, the right as viewed in Fig. 4, spring I43 returns valve element I33 to its inner position, subjecting the area between flexible diaphragm I5 and end cap H to atmospheric pressure through the aperture in end plate I 22, recess I31, passageways I35 and M3, port iSI and passageway I29. As piston element 25 nears the end of its path of movement, it abuts against spring I49 causing it to build up a pressure sufficient to overcome the pressure of spring I 55. When this occurs valve element I45 will move inwardly until conical tip I5I closes the aperture in member I52.

However, member I52 will not be moved outwardly from its position against the inner end of the enlarged portion of recess E38, because at this point the area between flexible diaphragm 'l and end cap '36 will be subject to an exhaust action through opening [46, recess 36, passageways I34 and I32, port I30, and passageway i 28. The flex-- ible diaphragms M and i5 will then flip over to their outer position causing piston elements 25 and 26 to reverse their respective directions of movement. Thus, piston element reverses its direction of movement somewhat before it abuts stop 52. I

This latter feature is of extreme importance because it causes the wiper blades to traverse a procletermined fixed path of movement well within the confines of the windshield molding, and permits the wiper blades to assume a parked position against the bottom edge of the windshield, thus eliminating the objectionable slapping of the wiper blades against the windshield molding and at the same time causing the wiper blades to assume a parked position which is out of the path of vision of the driver.

To illustrate this feature, let it be assumed that the piston element 25 has just begun its movement to the right, as illustrated in Fig. i, the left as illustrated in Fig. 1, and that the driver actuates Bowden wire 28 to move plate I53 to its parked position as illustrated in Fig. 9. This will cause the left hand side of piston element 25 and the right hand side of piston elemen 26, as viewed in Fig. 1, to remain in communication with vacuum line I3 through ports and T6, passageway 65, port t3, passageways and 83, opening II i5, port 89, and passageway '53. At the same time, the right hand side of piston 25 and the left hand side of piston 25, as viewed in Fig. 1, remain subject to atmospheric pressure through ports I58 and 6'5, passageway 65, port 89, passageway er, the interior of cover 93, opening 9I, filter packing 92 and opening ed. The pressure (inferential thus created remains the same even when piston element 25 abuts spring I 39 to move valve It?) outwardly, causing the flexible diaphragms to flip over to their other position, because the exhaust connection remains the same, and the atmospheric connection is blocked, extending from passageway 8? to port 8d, passageway ill and opening iI I.

Therefore piston 25 continues its movem nt, moving member I52 until member I52 abuts against member L53, at which point piston 25 will also abut stop i5"! and cease its movement. This small amount of continued movement of piston 25 and consequently wiper blades lii and 42, when plate I I 3 is in its park position, permits wiper blades as and 42 to assume a parked position against the bottom edge of the windshield, although during a windshield cleansing 9 operation the wiper blades do not touch either the side or bottom edge of the windshield. In this manner, the present invention prevents the annoying slap of the wiper blades against the windshield moulding when a windshield cleansing operation is in progress, and at the same time causes the wiper blades to assume a parked position against the bottom edge of the windshield and out of the drivers path of vision whenever the windshield cleansing operation is arrested.

It is noted that this form of the invention is particularly desirable because diaphragms 14 and 15 provide hermetic seals for the two remote suction chambers, whereby the pressure differential applied to donkey engine a is fully utilized. There is no possible leakage of air since guide member I02 is connected to diaphragms 14 and 15 on the outer sides thereof, which sides are remote from the suction chambers, and there are no sliding joints into the suction chambers which require stuffing boxes or other packing. Thus, the controller is highly efiicient and satisfactory operation can be achieved with a minimum of pressure.

A modified form of donkey engine is illustrated in Figs. 10 through 13, which modified form comprises a body portion I58 having attaching ears I59 and IE9 integral therewith. Bolts I8I and IE2 extend through ears I59 and IE9, respectively, and serve to mount body portion I58 on motor casing I. Body portion I58 has a cylindrical bore I69 extending longitudinally there through, and end caps I64 and I65 serve to cover the ends of bore I53. I61 extend from, the rear of body portion I58 transversely therethrough, communicating with bore I69 at points near the ends thereof. At their opposite ends, passageways I96 and I61 are adapted to communicate with ports I39 and I'SI, respectively, in motor casing I. A passageway I68 extends from the rear of body portion I58 transversely therethrough and communicates at one end with bore I93 at a point near the center thereof. At its other end, passageway I68 is adapted to communicate with port 89 in motor casing I. A fourth passageway I69 extends from the rear body portion I58 transversely therethrough to a point near bore I83,

at which point it communicates with a vertical passageway I19, extending upwardly to the top of body portion I58. At its other end, passage way I99 is adapted to communicate with port -88 in motor casing I. Two other vertical passageways I1! and I12 extend from bore I63 to the top of body portion I58. A longitudinal passageway I13, within the top part of the body portion I58, is adapted for connection with vacuum line I9 and has two ports I14 and I15 extending therefrom to the top of body portion I58. Mounted for movement across the top of body portion I58 is a plate I16 having openings I11 and I18 therein. Opening I11 is adapted to place passageway I1 I and port I14 in communication when plate I18 is in running position. Opening I13 is adapted to place passageways I10 and I12 in communication when plate I16 is in running position, and places passageway Passageways I56 and I19 and port I15 in communication when plate 7 ,around. A suitably groovedboss ISI is formed on body portion I58, and a correspondingly grooved member I82, securedthereto by a bolt I83, cooperates therewith for the reception of Bowden wire 20. The end of Bowden wire 29 is attached to a projection I84 on plate I89. A guide member I85 extends over plates I89, I19 and I16 and is attached to body portion I58 by means of bolts I86. In this way, plate I18 is permitted a longitudinal back and forth movement-across the top of body portion I58, assuming either a running or a park position.

Body portion I58 has a recess It! in the front part thereof, which recess is filled with a filter packing I88. Packing I98 is held in place within recess I81 by means of a plate I89 having an opening I99 therein. Passageways I9I and I92 extend transversely through body portion I58 between bore I83 and recess I81.

The bore I 69 has a piston I93 therein. Piston I99 comprises a piston rod 195 having hubs I95. I95, I91 and I98, of the same diameter as the bore, formed integral therewith. The ends I99 and 289 of piston rod I99 are of reduced diameter and act as stop members.

The operation of this modified form of donkey engine is as follows.

Let it be assumed that piston elements 25 and 26 are in their park positions as illustrated in Fig. l, and that plate I16 has just been moved to its running position, shown in solid lines in Fig. 13. Piston I93 will have moved to the dotted line position shown in Fig. 11, because the area between hub I98 and end cap I99 will have been exposed to atmosphere through passageway I61, port ISI, passageways I33 and, I95, recess I31 and the aperture in plate I82, and the area between hub I95 and end cap I64 will have been subject to exhaust through passageway I69, port I99, passageways I92 and [38, recess I39, opening I49, port 99, passageway 86, port 88, passageways I89 and I19, opening I'I'8, passageway I12, bore I69 between hubs I95 and I91, passageway III, opening I11, port I14 and passageway I13.

The pressure diiferential thus created would have moved piston I94 to its dotted line position during the parking stroke of piston 25.

In this position, the right hand side of piston 25 and the left hand side of piston 29, as viewed in Fig. 1, will be subject to a partial vacuum through ports 88 and 81, passageway :95, port 89, passageway I98, bore I83 between hubs I96 and I91, passageway I1I, opening I'II, port I14, passageway I13 and vacuum line I3. At the same time, the left hand side of piston 29 and the right hand side of piston 28 as viewed in Fig. 1, will be subjected to atmospheric pressure through ports 69 and 19, passageway 68, port 88, passageways I69 and I18, opening I18, passageway I12, bore I63 between hubs I91 and I98, passageway I92, filter packing I88 and opening I99. pressure differential thus created will cause pistons 25 and 28 to move to the right and left, respectively, as viewed in Fig. 1, which will in turn move cables III and 35 to impart movement to wiper blades 48 and 42, causing them to move outwardly upon the windshield.

As it nears the end of its movement to the right, as viewed in Fig. 1, piston 25 will abut against boss I II on valve member I88, pushing the same outwardly against the action of spring M3. This will expose the area between hub I98 and end cap I95 to exhaust action through passageway I91, port I9I, passageways I93 and I35, recess I91, grooved member I99 and opening I44. At the same time the area between hub I99 and end cap I94'will be subject to atmospheric pressure through passageway I96, port I39, passage- The way 32 and IE5, recess I36, and the apertures in members I52 and 153. The pressure differential thus created causes piston I93 to move to the full line position shown in Fig. 11. In this position, the left hand side of piston 25 and the right hand side of piston 26, as viewed in Fig. 1, will be subject to exhaust through ports E9 and iii, passageway 66, port 88, passageways I69 and ii opening H8, passageway I12, bore I63, passageway i'II, opening I'll, port I'Id, passageway H3 and vacuum line 53. At the same time, the right hand side of piston 25 and the left hand side of piston 26, as viewed in Fig. 1, will be subject to atmospheric pressure through ports $8 and El, passageway 55, port 39, passageway 53, bore I63 between hubs I95 and I95, passageway I9I, filter packing I88 and opening I99. Near the end of its path of movement, piston 25 will abut spring Ids to move valve I45 outwardly, causing the pistons to reverse their direction of movement in the manner previously explained. This back and forth movement of piston elements 25 and 2d, and consequently wiper blades 49 and 42, continues as long as plate Ilil remain in running position.

When it is desired to arrest the windshield cleansing operation, plate I'Ifi is moved to its park position, such position of openings Ill and lit being shown in dotted line in Fig. 13. In this position, the left hand side of piston 25 and the right hand side of piston 25, as viewed in Fig. l, are kept subject to exhaust action through ports ri and 76, passageway 66-, port 88, passageways ass, and H0, opening I78, port I75, passageway H23 and vacuum line I3. Since these connections completely bypass bore IE3, any movement of piston I33 therein has no effect on the parking movement of the wiper blades. The novel parking means operates in the manner previously described to cause wiper blades Q8 and to assume a position of rest against the bottom edge of the windshield.

Having fully disclosed the present. invention, and completely described the method of operation thereof, what i claimed as new is:

l. A windshield cleaner comprising a plurality of wiper blades, mounting means for said blades designed to impart an oscillatory motion thereto, a plurality of piston type suction motors each having a piston rod extending therethrough, means in operative engagement with said mounting means and connected to the opposite ends of each of said piston rods forming therewith an endless power transmitting means for imparting motion to said wiper blades, means creating a pressure differential in each of said motors, and means responsive to movement of the pistons in said motors for reversing said pressure, diiferential.

2. A windshield cleaner comprising wiping means, a suction motor drivingly connected to said wipin means, control means adapted to reverse the pressure differential in said motor, control means including valve means and a pair of opposed pressure chambers for actuating said valve means, a flexible wall hermetically sealing each of said pressure chambers, connect ing mean; extending between said valve means and the side or" said flexible walls externally of said pressure chambers, and pilot valve means responsive to a predetermined movement of said motor in either direction and connected to said pressure chambers for reversing the pressure diff-erential between said pressure chambers.

3. A windshield cleaner comprising dual wiper blades, spaced mounting means for said blades designed to impart an oscillatory motion thereto, a pair of piston type fluid motors each having a piston rod extending therethrough, a pair of fiesible power transmission elements each in operative engagement with a respective one of said mounting mean and connected at its opposite ends to one end of each of said piston rods, said transmission elements and said piston rods forming an endless power transmitting unit for imparting motion to said wiper blades, means creating a pressure differential in each of said motors, and means responsive to movement of the pistons in said motors for reversing said pressure differential.

i. A windshield cleaner comprising plural motors each with a fluid pressure responsive member movable back and forth, flexible power transmission elements having their opposite ends connected respectively to the pposite sides oi the pressure responsive members to form therewith an endless power transmitting unit, space wiper means each operatively engaged with a respective one of said transmission elements, means creating reverse iiuid pressure differentials in said motors, and means for reversing said pressure differentials concurrently, whereby the fluid pressure acts directly upon each side of the endless member.

5. A windshield cleaner comprising plural motors each with a fluid pressure responsive member movable back and forth, a plurality of power transmission elements each ha ing a pair of reversely reciprocable power input ends, said elements having their pow-er input ends connected respectively to the opposite sides of the pressure responsive members to provide in effect therewith an endless power transmitting unit, spaced wiper means each operatively engaged with a respective one of said transmission elements, means creating a fluid pressure differential in each of said motors, and means for reversing said pressure differentials, whereby the fluid pressure act directly upon each side or the endless member.

6. A windshield cleaner comprising a pair of wiper means, mounting means for said wiper means designed to impart an oscillatory motion thereto, a pair of mechanically independent fiuid pressure motors each having a double ended fluid pressure driven part movable back and forth, endless power transmission means in operative engagement at opposite return portions thereof with said mounting means for imparting motion to said wiper blades and including one of said parts in one side and the other part in th other side as continuous portions thereof, means creating a substantially equal pressure dififerential in each of said motors, and means adapted for reversing said pressure differential.

7. A windshield cleaner comprising a plurality of wiper blades mounted for oscillatory movement across a windshield, each of said wiper blades having a drive part adapted to be actuated by back and forth movement, a plurality of mechanically independent fluid motors each having a fluid pressure driven member therein, endless tension transmitting means in operative engagement with each of said drive parts and including said driven members connected therin at substantially symmetrical points therealong, means creating a substantially equal pressure differential in each of said motors, and means automatically reversing said pressure differential as said wiper blades reach either end of their path of movement.

' 3. A windshield cleaner comprising plural motors each with a fluid pressure responsive member movable back and forth, flexible power transmission elements having their opposite ends connected respectively to the opposite sides of the pressure responsive members to form therewith an endless power transmitting unit, spaced wiper means each operatively engaged with a respective one of said transmission elements, control means adapted to reverse the pressure diiferential in said motors, said control means including a piston type valve means and a pair of opposed pressure chambers for actuating said valve means, said piston type valve means forming one wall in each of said pressure chambers, and pilot valve means responsive to a predetermined movement of said one of said motors in either direction and connected to said pressure chambers for reversing the pressure differential between said pressure chambers.

9. A windshield cleaner comprising a plurality of Wiper blades having a predetermined path of movement, a drive part connected to each of said wiper blades and adapted to be actuated by back and forth movement, mechanically independent dual suction motors each having a separate double-ended translational power output member, means including cable means and said power output member forming an endless drive means in operative engagement with each wiper blade drive part, means creating a substantially equal pressure difierential in each of said motors, and means automatically reversing said pressure differential when said wiper blades reach either end of their path of movement.

10. A windshield cleaner driving means comprising dual suction motors adapted for connection to a plurality of wiper blades, a piston movable through a predetermined path in each of said motors, means including power valve means creating a pressure difierential in each of said motors, pilot valve means having a first position responsive to one of said pistons reaching the end of its predetermined path for actuating said power valve means for reversing the pressure dififerential in each of said motors thereby imparting a reciprocating motion to said pistons, and means causing said pistons to assume a position of rest beyond one end of their predetermined path when the motion thereof is arrested, said pilot valve means having a second position corresponding to the position of rest of the wiper blades to enable said pistons to assume said position of rest.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 7 1,206,960 Wilkins Dec. 5, 1916 1,424,890 Tolberth Aug. 8, 1922 1,516,722 Folberth et al Nov. 25, 1924 1,725,436 Williams Aug. 20, 1929 2,045,140 Horton et a1. June 23, 1936 2,209,921 Horton July 30, 1940 2,298,197 Coffey Oct. 6, 1942 2,547,175 Sacchini Apr. 3, 1951 2,547,285 Rappl Apr. 3, 1951 FOREIGN PATENTS Number Country Date 282,372 Great Britain of 1928 

